Column-mounted shoring bracket assembly for overhead formwork

ABSTRACT

A column-mounted shoring bracket adapted for use in first supporting a concrete slab-supporting formwork beam during concrete-pouring operations, then stripping the formwork from the hardened slab and lowering the thus released formwork, and finally permitting lateral withdrawal of the formwork from beneath the completed slab for purposes of reuse at a higher building level. A roller support for the beam is carried on a vertically slidable carriage which transfers the load of the beam to the lower end of a jack screw which is thus placed under tension. Rotation of the jack screw for carriage-lowering purposes places the jack screw under further tension and effects an initial stripping of the formwork from the slab immediately prior to lowering of the formwork.

United States Patent 1 1 Gregory et a1.

[ 1 Oct. 22, 1974 1 v COLUMN-MOUNTED SHORING BRACKET ASSEMBLY FOROVERHEAD FORMWORK [75] Inventors: R. Kirk Gregory, Barrington;

Robert J. Flathau, Palatine, both of I11.

[73] Assignee: Symons Corporation, Des Plaines,

Ill.

22 Filed: June 4,1973

211 Appl. No.: 366,434

[52] US. Cl. 248/295, 249/219 R [51] Int. Cl..... A47f 5/10, A47h 33/10,E04g 17/16 [58] Field of Search 248/205 R, 295, 296, 298,

[56] References Cited UNITED STATES PATENTS 3,504,879 4/1970 Strickland248/296 3,771,753 11/1973 Wilbur 248/295 3,776,499 12/1973 Turner249/219 R X 3,779,500 12/1973 Cox 249/219 R X Primary Examiner-J.Franklin Foss Attorney, Agent, or Firm-Norman l-l. Gerlach 5 7] ABSTRACTA column-mounted shoring bracket adapted for use in first supporting aconcrete slab-supporting formwork beam during concrete-pouringoperations, then stripping the formwork from the hardened slab andlowering the thus released formwork, and finally permitting lateralwithdrawal of the formwork from beneath the completed slab for purposesof reuse at a higher building level. A roller support for the beam iscarried on a vertically slidable carriage which transfers the load ofthe beam to the lower end of a jack screw which is thus placed undertension. Rotation of the jack screw for carriage-lowering purposesplaces the jack screw under further tension and effects an initialstripping of the formwork from the slab immediately prior to lowering ofthe formwork.

7 Claims, 4 Drawing Figures COLUMN-MOUNTED SIrllOlRING BRACKET ASSEMBLYFOR OVERHEAD FURMWORK The present invention relates to a column-mountedshoring bracket for supporting pallet-type concrete slab formwork duringconcrete pouring operations and, thereafter, after the concrete hasbecome set, facilitating lowering of the formwork away from thecompleted slab while at the same time stripping the formwork from theslab and then shifting the formwork laterally from beneath the slab forreuse elsewhere in the building undergoing erection. The invention isparticularly concerned with a column-mounted shoring bracket of thescrew jack type wherein the load-bearing member of the bracket embodiesa leveling screw which supports the formwork during concrete-pouring andhardening operations and which, thereafter, is operated to pull theformwork downwardly and thus strip the same from the slab, after whichtractional roller means forming a part of the shoring bracket allows theformwork to be shifted laterally for removal purposes.

Shoring brackets which operate upon the screw jack principle have beenin use for quite some time, and so have brackets which, after loweringof the formwork, have facilities for tractionally rolling the formworklaterally out from beneath the concrete slab. I-Ieretofore, all suchexisting or conventional shoring brackets of the general character underconsideration are predicted upon the use of a screw jack which supportsthe load in compression, thus requiring the use of a relatively massivejack screw to withstand the load. Due to the relatively great length ofthe jack screw, the latter is subject to bending stresses, particularlyat such time as it is fully extended for slab-supporting purposes duringand after concrete-pouring operations.- Construction operations whichmay be carried out above slab level after the concrete of the slab hashardened may effect load-shifting phenomena of sufficient magnitude asto initiate jack screw bending and once such bending of the jack screwhas begun, the screw is greatly weakened and further bending will takeplace to completion and possible fracture.

The present invention is designed to overcome. the above-notedlimitation of compressional failure of the jack screws which areassociated with currently known shoring brackets and, toward this end,the invention coontemplates the provision of a novel composite shoringbracket wherein the vertically extending jack screw which supports aboveit the load-bearing traction roller or rollers functions in tension tosupport the load so that even when the effective length of the jackscrew is at its maximum, i.e., when the associated formwork is in itsuppermost slab-supporting position, the tension in the jack screw has atendency to maintain the jack screw linearly straight rather than in abent position. By such an arrangement, a considerably lighter jack screwthan has heretofore been used in connection with shoring brackets of thetype under consideration may be employed.

The provision of a shoring bracket of the jack screw type wherein, asaforesaid, the jack screw functions in tension to support and lower theload (associated formwork) constitutes the principal object of thepresent invention; Briefly, in carrying out this object, the inventioncontemplates the provision of a novel shoring bracket wherein theload-bearing traction roller means, instead of being mounted directly onthe upper end of the jack screw, is mounted on the upper end of a slidemember which is vertically slidable on a fixed part of the bracket. Thejack screw is effective between the lower end of the bracket and suchfixed part of the bracket and thus the load, which is carried by thebracket, is transmitted through the slide member to the lower region ofthe jack screw, thereby placing the latter under tension during the timethe formwork rests on the roller means on the slide member.

A further limitation that is attendant upon the construction and use ofconventional column-mounted shoring brackets resides in the fact thatsuch brackets are invariably fixedly mounted in toto on their respectivebuilding columns, thus requiring the use of a large number of suchbrackets during the erection of any given multi-story building. Sinceeach bracket is of a composite nature and involves a large number ofparts,

both moving and stationary, duplication of these brackets throughout thebuilding framework entails a large bracket inventory. Where theindividual' brackets are removable in their entirety from the columnsfor reuse in the same building installation, the labor that is involvedin transferring them from one column to another on a different storylevel appreciably increases erection costs. The present shoring bracketobviates this latter limitation in that it is of two-part construction,one part being in the form of a fixed bracket support part which is ofan inexpensive nature and is temporarily left in position on itsassociated column, and the other part being a removable part whichincludes the jack screw and its associated aforementioned slide member.By such an arrangement, the removable bracket part which is by far themost costly, may be transferred from column to column, the transferbeing made with a minimum of effort and the anchoring-of the removablepart to the fixed part being accomplished by the simple expedient ofplacing a fast pin in position.

Additional objects and advantages of the invention, not at this time setforth, will become readily apparent as the following description ensues.

The invention consists in the several novel features which arehereinafter set forth and are more particularly defined by the claims atthe conclusion hereof.

In the accompanying two sheets of drawings forming a part of thisspecification or disclosure, one illustrative embodiment of theinvention is shown.

In these drawings:

FIG. 1 .lS a fragmentary perspective view of a concrete floor slab forminstallation, such view showing one of theimproved column-mountedshoring brackets of the present invention operatively installed thereinwith the illustrated bracket being shown in its loadsupporting position;

FIG. 2 is an enlarged perspective view of the shoring bracket of FIG.ll;

FIG. 3 is a vertical transverse sectional view of the bracket; and

FIG. 4 is an exploded perspective view of the improved column-mountedshoring bracket.

Referring now to the drawings in detail and in particular to FIG. 1, ashoring bracket embodying the principles of the present invention isdesignated in its entirety by the reference numeral 10 and is shown asbeing operatively installed upon a precast vertical concrete column 12which is associated with and forms a part of a building undergoingerection. The function of the bracket is, in combination with identicalbrackets which are applied to other columns of the building, to

to permit lateral removal of the formwork from beneath the slab.

Formwork such as the formwork l4 herein disclosed will vary widely indifferent building installations. The particular formwork selected forillustration herein is only fragmentarily disclosed and it includes alongitudinal beam or stringer 16, aa transverse beam member 18, and aplywood or other deck on which the wet slab-forming concrete is pouredfor ultimate production of the floor slab (not shown). The shoringbracket 10 serves to support the associated beam 16 duringconcrete-pouring operations and, as will be described. presently; afterthe concrete has become set, the bracket is capable of manipulation forthe purpose of lowering the stringer 16, and consequently, the entireformwork 14. After the lowering operation, certain tractional rollermeans which is associated with the bracket 10 affords a substantiallyfrictionless support for the lowered pallet-type formwork so that it maybe slid endwise for use elsewhere.

Referring now to FIGS. 2, 3 and 4 of the drawings, the improved shoringbracket 10 involves in its general organization two main componentparts, namely, a

' backing plate 30 and are adapted for reception therethrough of theshank portions of respective bolts (not shown) by means of which thefixed shelf part 22 as a whole may be fixedly secured in position on theassociated concrete column 12. Small pin-receiving holes 36 are formedin the upper portions of the shelf plates 32 and these are adapted forthe reception of respective fast pins 38 by means of which the jack part24 may be removably secured to the shelf part 22.

The jack part 24 of-the shoring bracket 10 is comprised of threeprincipal components, namely, a base frame 40, a vertically shiftableload-supporting carriage 42, and a vertical jack screw 44 by means ofwhich the carriage 42 is caused to travel or move vertically withrespect to the base frame 40. In FIGS. 2 and 3 of the drawings, the baseframe 40 and the carriage 42 are shown in their effective assembledrelationship, while in FIG. 4, said base frame and carriage 4t) and 42are separately illustrated in detached form.

The base frame 40 of the jack part 24 of the shoring bracket 10 consistsof three spaced apart, horizontally extending parallel frame platesconsisting of a pair of outside plates 50 and a relatively wide medialor central plate 52 (see FIG. 4). The three plates are maintained intheir spaced relationship by means of front and rear,

horizontally extending angle pieces 54 and 56. An angle bracket 58 iswelded to the forward end of one frame plate 50 and an angle bracket iswelded to the rear end of the other plate 50. These two angle bracketsare disposed diagonally opposite one another and have depending partswhich are provided with holes 60. The latter are designed for registerwith the aforementioned holes 36 in the shelf plates 32 of the shelfpart 22 of the shoring bracket 10 when the base frame 40 is applied tosaid shelf part. A hole 62 (see FIGS. 3 and 4) is formed centrally inthe medial or central plate 52 of the base frame 40 for slidablereception of the upper end of the aforesaid jack screw 44. The latter isassembled upon the base frame 40 by first projecting the upper end ofthe same upwardly through the hole 62 after which a nut 64 is welded onsuch upper end while a loose collar 66 is then positioned on the jackscrew 44 directly beneath the plate 52. Thereafter, a set collar 68 ismounted on the jack screw immediately beneath the loose collar 66. Thenut 64, together with the collars 66 and 68, establishes a swivelconnection for the upper end of the jack shaft 44.

The vertically shiftable carriage 42 of the bracket jack part 24 is ofcage-like design and includes a pair of vertically extending channelpieces 70 which are disposed in back-to-back spaced apart relationshipand are fixedly connected together at their lower ends by a transversebottom plate 72. The plate 72 is preferably welded in place and hasformed therein a central opening 74. A nut 76 iswelded in position tothe underneath side of the plate 72 so that its threaded bore is inregister with the opening 74. The nut 76 threadedly receives the lowerend portion of the jack screw 44 as clearly shown in FIGS. 2 and 3 ofthe drawings. The upper ends of the two channel pieces 70 are fixedlycon nected together by means of a pair of transverse plates and theseconsist of a front plate 78 and a rear plate 80 (see FIG. 4).

Means are provided at the upper end of the carriage 42 for tractionallysupporting the beam or stringer 16 of the pallet-type formwork 14 duringthe time that the concrete is being poured on the deck plate 20, as wellas during lowering of the formwork 14, and also during the time that theformwork is being rolled out from beneath the previously completed slab.Accordingly, a horizontally disposed, transversely extendingrollersupporting shaft 82 has its end regions rotatably journaled inaligned circular holes in the front and rear plates 78 and 80 andcarries a load-supporting roller 84, the axial extent of which isslightly less than the distance between the plates 78 and 80, the rollersubstantially spanning such distance. The shaft 82 also carries anoutside roller 86 of frustoconical design, the small base of theroller'being disposed inwardly and facing the front plate 78. The roller86 is of larger over-all diameter than the roller 84 and constitutes anedge guide roller for the purpose of preventing rolling of the beam orstringer l6 sidewise from the roller 84.

Various ways of assembling the base frame 40 and the carriage 42 of thebracket jack part 24 may be resorted to, one such way being to assemblethe carriage 42, leaving the bottom plate 72 the last to be mounted andsecured in place as indicated by the dotted line position of such platein FIG. 4. Prior to welding the bottom plate 72 in position, the lowerend portions of the two channel pieces 70 are inserted endwise throughthe voids 90 (see FIG. 4) which exist between the central plate 52 andthe two side plates 50 of the base frame,

after which the plate 72 may be welded in position, thus causing thecarriage 42 to be captured by the base frame 40. Thereafter, the jackshaft 44 may be threaded upwardly through the nut 76 so that it projectsthrough the opening "74, after which the upper end of the jack shaft,the nut 64, and collars 66 and 68 may be assembled in position in themanner previously indicated.

In the installation and operation of the herein described shoringbracket in association with a multistory or high-rise concrete building,the requisite number of brackets 10 will be mounted on the concretecolumns of the building in order to accommodate the particularpallet-type formword 14 being utilized in the formation of a concretefloor slab above the formwork 20. The various jack screws, the lowerends of which are provided with square end portions 92 for facilitatingmanipulation by a wrench or other suitable turning tool, will beadjusted to bring the associated rollers 84, 86 approximately to thesame general horizontal plane at the desired deck height, andthereafter, the formwork 14 will be lowered onto or otherwise caused torest upon the rollers 84. Initial application of each bracket 10 to acolumn 12 is made by bolting the shelf part 22 to the column and,thereafter, applying the jack part 24 to the thus fixed shelf part 22.Such application is made by setting the jack part on the upperhorizontal edges of the triangular plates 32 and causing the holes 60 inthe angle brackets 58 to register with the holes 36 in the triangularshelf plates. Thereafter, the fast pins 38 are passed through theregistering holes in order to lock the two bracket parts 22 and 24together.

In the operation of the shoring bracket 10, it will be noted from aninspection of FIG. ll that the beam or stringer l6 rests squarely on theroller 84 while the roller 86 serves as an edge guide for preventinginadvertent derailing of the beam or stringer. At such time as thepallet-type formwork 14 is thus'positioned on the various brackets, aleveling operation may be instituted so as to bring the plywood deck 26to the desired level. Also at this time, slight longitudinal adjustmentof the formwork may be resorted to if necessary.

With the formwork 14 thus resting on the rollers 64, pouring of theconcrete or other forming operations are conducted and when it is timeto remove the formwork the jack screws 44 of the brackets ill) aremanipulated by application of a suitable wrench or the like to thesquared ends 92 thereof so as to lower the loadsupporting carriages 42,thereby also lowering bodily the formwork as a whole away from thecompleted superjacent floor slab. When it is ascertained that theformwork is at a proper level for removal thereof from the installation,it can readily be rolled longitudinally on the roller 84 out frombeneath the formed slab.

In most instances, upon release of upward pressure on the formwork 14,there is a tendency for the plywood deck to remain adhered to thehardened concrete thereabove. In such a situation, it is customaryforcibly to pull the formwork, or pry it, from its ad hered position. Inthe present instance, loosening of the bond between the deck 26 and theconcrete may be effected by passing a chain or metal strapping aroundthe beam 16 and causing it to be hooked to or engaged with anyappropriate part of the movable carriage 24 of each or any one of theshoring brackets 16 so that lowering of the carriage under the influenceof the jack 7 on the jack screws.

screw 44 will exert a powerful downward pull upon the formwork 114, thecombined pull of all of the carriages 24 associated with the variousbrackets ll) being adequate for deck dislodgment.

It is to be noted that in connection with the operation of the hereindescribed shoring bracket 10, the load of the formwork is at all timesapplied to the jack screw 44 in tension, such tension existing in thatportion of the jack screw which extends between the medial plate 52 andthe base frame 40 and the bottom plate 72 of the carriage. While therelatively sturdy carriage 24 remains in compression, the jack screw 44remains in tension. By such an arrangement, it is not necessary toemploy the relatively massive jack screws which ordinarily areassociated with shoring brackets of the type where the formwork loadsplace a direct compressional thrust The invention is not to be limitedto the exact arrangement of parts shown in the accompanying drawings ordescribed in this specification as various changes in the details ofconstruction may be resorted to without departing from the spirit orscope of the invention. Therefore, only insofar as the invention isparticularly pointed out in the accompanying claims is the same to belimited.

Having thus described the invention what we claim as new and desire tosecure by letters patent is:

1. A shoring bracket adapted to support a horizontal I stringer forminga part of a concrete-receiving, pallettype formwork used in the erectionof a multi-story building, said bracket comprising a horizontal baseframe having means whereby it may be fixedly secured to a verticalcolumn of the building, a vertically elongated carriage mounted withrespect to the base frame so that it is slidable vertically between araised and a lowered position, a loadbearing roller on the upper end ofsaid carriage, a vertical jack screw having its upper end swivellyconnected to the base plate and depending therefrom, and meansestablishing a threaded connection between said jack screw and the lowerregion of the carriage, whereby rotation of the jack screw in oppositedirections will effect raising and lowering of the carriage and formworkwith the intervening region of the jack screw between such threadedconnection and base frame supporting the carriage and formwork undertension.

2. A shoring bracket as set forth in claim 1 and wherein said shoringbracket is of a composite two-part separable nature and includes a shelfpart designed for permanent and fixed attachment to the vertical columnof the building and a jack part removably mounted on the shelf part,said jack part embodying said base frame.

3. A shoringbracket as set forth in claim 2 and wherein said shelf partincludes a backing plate designed for face-to-face application to thebuilding column, and a shelf member projecting forwardly from saidbacking plate, base frame is removably supported on said shelf member,and there is provided releasable locking means effective between thebase frame and shelf member for maintaining the former in position onthe latter against dislodgment.

4. A shoring bracket as set forth in claim 3 and wherein said shelfmember comprises a pair of vertically disposed spaced apart shelf platesdisposed in edge-to-face relationship with respect to said backing plateand presenting horizontal upper edges upon 6. A shoring bracket as setforth in claim 5 and wherein said side members are connected together attheir lower ends by a bottom plate which carries a nut through which thejack screw extends.

7. A shoring bracket as set forth in claim 6 and wherein said jack screwprojects upwardly through said carriage centrally thereof and betweensaid side members.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,843,084 Dated October 22 1974 Inventor(s) R. Kirk Gregory and Robert J.Flathau It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Claim 2, line 7, after "frame" insert the carriage and the jack screw--.

Claim 3, line 5, after plate, insert --the-, and after "frame insert--of the jack part--.

Claim 4, line 6, after "rest" insert --s1idably--; and

line 10, after "base" insert --frame--.

Claim 5, line 3, after "voids," insert -and--.

Claim 6, line 2, after "members" insert --of the carriage--.

Signed and sealed this 24th day of June 1975.

(SEAL) Attest:

C MARSHALL DANN RUTH C. i-[ASON Commissioner of Patents AttestingOfficer and Trademarks FORM PO-1050 (10-69) USCOMM-DC 60376-P69 k v.5.GOVERNMENT PRINTING OFFICE: I"! 0-366-334,

1. A shoring bracket adapted to support a horizontal stringer forming apart of a concrete-receiving, pallet-type formwork used in the erectionof a multi-story building, said bracket comprising a horizontal baseframe having means whereby it may be fixedly secured to a verticalcolumn of the building, a vertically elongated carriage mounted withrespect to the base frame so that it is slidable vertically between araised and a lowered position, a loadbearing roller on the upper end ofsaid carriage, a vertical jack screw having its upper end swivellyconnected to the base plate and depending therefrom, and meansestablishing a threaded connection between said jack screw and the lowerregion of the carriage, whereby rotation of the jack screw in oppositedirections will effect raising and lowering of the carriage and formworkwith the intervening region of the jack screw between such threadedconnection and base frame supporting the carriage and formwork undertension.
 2. A shoring bracket as set forth in claim 1 and wherein saidshoring bracket is of a composite two-part separable nature and includesa shelf part designed for permanent and fixed attachment to the verticalcolumn of the building and a jack part removably mounted on the shelfpart, said jack part embodying said base frame.
 3. A shoring bracket asset forth in claim 2 and wherein said shelf part includes a backingplate designed for face-to-face application to the building column, anda shelf member projecting forwardly from said backing plate, base frameis removably supported on said shelf member, and there is providedreleasable locking means effective between the base frame and shelfmember for maintaining the former in position on the latter againstdislodgment.
 4. A shoring bracket as set forth in claim 3 and whereinsaid shelf member comprises a pair of vertically disposed spaced apartshelf plates disposed in edge-to-face relationship with respect to saidbacking plate and presenting horizontal upper edges upon which the sideedges of said base frame rest, and said releasable locking meansembodies a pair of fast pins which project through pairs of alignedopenings in the shelf plates and depending fastening brackets which aremounted on the base.
 5. A shoring bracket as set forth in claim 3 andwherein said base frame is provided with laterally spaced voids, thecarriage is of cage-like construction and embodies a pair of sidemembers which are slidable through said voids.
 6. A shoring bracket asset forth in claim 5 and wherein said side members are connectedtogether at their lower ends by a bottom plate which carries a nutthrough which the jack screw extends.
 7. A shoring bracket as set forthin claim 6 and wherein said jack screw projects upwardly through saidcarriage centrally thereof and between said side members.